Multi-layer body support having phase change material

ABSTRACT

A body support includes a plurality of vertically stacked layers, a phase change material provided in each of the layers, and a cover enclosing the vertically stacked layers.

FIELD OF THE INVENTION

The present invention relates to body supports. More specifically, the present invention relates to multi-layer foam body supports and methods of manufacturing the same.

BACKGROUND OF THE INVENTION

Body supports for supporting any portion or all of a human or animal body are generally known in the art, and are typically deformable structures in the form of a mattress, pillow, or cushion, including those for use in beds, seats, or chairs. Body supports may be any desired shape or size suitable to support a portion, up to and including the entirety, of the user.

Known body supports may be constructed of a single layer of material. For example. a body support may be constructed of a single layer of natural material such as straw, cotton, feathers, air within one or more bladders, metal springs, or synthetic material such as synthetic foam. Still other body supports may be constructed of multiple layers of different materials. For example, some body supports are made of two or more layers of different synthetic foams, such as viscoelastic or non-viscoelastic polyurethane foam, and/or latex foam.

Body supports constructed of one or more layers of synthetic foam have certain desired properties. For example, certain synthetic foams conform to a user, distributing the user's weight and reducing pressure points, This provides for more even support of the user and relieves pressure on joints, improving the user's level of comfort.

However, some known body supports constructed of one or more layers of synthetic foam may have certain undesirable properties. Body supports formed of some synthetic foams may have difficulty dissipating heat generated by the user (i.e., body heat). In some cases, the synthetic foam can absorb and retain heat generated by the user, resulting in the body support increasing, in temperature. The temperature increase of the body support is often undesirable, as it can lead to a decrease in the level of comfort of the user. For example, a user may experience sweating, restlessness, or general discomfort from the increased temperature of the body support.

SUMMARY OF THE INVENTION

The invention provides, in some aspects, a body support including a plurality of vertically stacked layers, a phase change material provided in each of the layers, and a cover enclosing the vertically stacked layers.

The invention provides, in other aspects, a body support including a plurality of foam layers, at least one of which is a high-resilience foam, and a phase change material provided within the high-resilience foam layer.

Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. is a perspective view of a body support in accordance with an embodiment of the present invention.

FIG. 2 is a partial cross sectional view of the body support of FIG. 1, taken along line 2-2 of FIG. I.

FIG. 3 is a cross-sectional view of an encapsulated phase change material.

FIG. 4 is a cross-sectional view of a phase change material without encapsulation.

Before any embodiments of the present invention are explained in detail, it should be understood that the invention is not limited in its application to the details, construction, or arrangement of components as set forth in the following description or as illustrated in the accompanying drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. It should be understood that the description of specific embodiments is not intended to limit the disclosure from covering all modifications, equivalents and alternatives falling within the spirit and scope of the disclosure. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting.

DETAILED DESCRIPTION

The invention illustrated in the accompanying Figures and described herein is generally directed to a multi-layer body support 100 having improved thermal capacity. By improving thermal capacity of the body support 100, the temperature of the body support is generally maintained, nominally increased, or slowly increased during use, improving the relative comfort of a user.

For ease of discussion and understanding, the following detailed description will refer to a body support 100, but illustrates the body support 100 as a mattress. It should be appreciated that a mattress is provided only for purposes of illustration. The features described herein in association with a body support are applicable to any suitable element or structure provided to support one or more body parts of a human or animal. Accordingly, a body support may include, but is not limited to, a mattress, mattress topper, overlay, futon, sleeper sofa, cushions, seat cushions, seat backs, pillows, neck pillows, leg spacer pillows, eye masks, or any other element or structure provided to support a portion, up to and including the entirety, of a human or animal. In addition, the body support may be any suitable or desired size or shape.

It should be appreciated that the term “relative comfort” of a user is directed to include how comfortable or physically content a user is in association with the temperature of the body support at any given moment in time. The term “relative comfort” may generally be a subjective level of physical comfort based upon the ambient temperature felt by a user at a given moment and which may be unique to one or more different users. “Relative comfort” may also change from moment to moment depending upon a number of different factors, for example, but not limited to, the ambient temperature outside the body support.

Referring now to the Figures, FIG. 1 illustrates a body support 100 including an upper or top surface 110 opposite a lower or bottom surface 112. As shown in FIG. 1, top and bottom surfaces 110, 112 may be substantially planar. In addition, top and bottom surfaces 110, 112 may be substantially parallel to one another. Alternatively, one or both of the top and bottom surfaces may be non-planar, for example, but not limited to, surfaces having ribs, bumps. waves, projections, protrusions of any shape and/or size, grooves, and/or apertures. Further, one or both of the top and bottom surfaces may be non-parallel, for example, but not limited to, surfaces having an arcuate, curved, convex, concave, angled, linear, and/or a non-linear profile.

Top and bottom surfaces 110, 112 may be separated by a plurality of foam layers 120, shown in FIG. 2. The foam layers 120 are provided between the top and bottom surfaces 110, 112 and extend a thickness T. Stated otherwise, thickness T extends between and separates top and bottom surfaces 110, 112. The foam layers 120 are not shown in FIG. 1, as body support 100 may include a cover or enclosure 114. Cover 114 may be provided to wrap around or enclose the foam layers 120. Cover 114 may provide a barrier to reduce wear of the foam layers 120, or act as a protective barrier to the foam layers 120. For example, cover 114 may provide a moisture barrier to limit or reduce penetration of liquids into the foam layers 120 and/or an allergen barrier to deter bacteria, dust mites, or other allergens.

Referring now to FIG. 2, the foam layers 120 may include a plurality or multiple layers of foam. Each of the foam layers may interact with one another to provide a desired soft and/or comfortable feel, while also providing adequate support for the user. The foam layers 120 may include two or more layers of foam, including, but not limited to. viscoelastic or non-viscoelastic polyurethane foam, latex foam, polyurethane foam, and/or any known or future developed suitable expanded polymer, such as expanded ethylene vinyl acetate, polypropylene, polystyrene, or polyethylene. The two or more layers of foam may include layers of similar or the same types of foam, or layers of different types of foam. In addition, the two or more layers of foam may include viscoelastic foam alternating with other layers of non-viscoelastic foam to provide body-conforming and low resilience benefits of viscoelastic foam while also exhibiting the “bounce” and overall support of conventional body supports.

The lowermost of the foam layers 120 is a base layer or foundation layer 122 of foam. Base layer 122 may be formed of high-resilience (HR) foam. The high-resilience foam may be high-resilience polyurethane foam. In one embodiment, the high-resilience foam may include any expanded polymer including, but not limited to, expanded ethylene vinyl acetate, polypropylene, polystyrene, polyurethane, or polyethylene.

The foam of base layer 122 may be a reticulated or non-reticulated foam. In this regard, non-reticulated foam includes a cellular structure in which walls of the individual cells are substantially intact. In contrast, reticulated foam is a cellular foam structure in which the cells of the foam are essentially skeletal. In other words, the cells of the reticulated foam are each defined by a plurality of apertured windows surrounded by cell struts. The cell windows of reticulated foam can be entirely gone (leaving only the cell struts) or substantially gone. Foam may be considered “reticulated” if a portion of the windows of the cells are missing (i.e.,. windows having apertures therethrough, or windows that are completely missing and therefore leaving only the cell struts). As a non-limiting example, foam may be considered “reticulated” if at least 50% of the windows of the cells are missing. Such structures can be created by destruction or other removal of cell window material, or preventing the complete formation of cell windows during the manufacturing process of the foam. Reticulated foam has certain characteristics which may be well suited for use in body support 100. Reticulated foam includes the enhanced ability to permit fluid movement through the foam, thereby providing enhanced air and/or heat movement within, through, and/or away from the layer made of reticulated foam.

Base layer 122 may have a hardness of greater than about 80 N and no greater than about 200 N. This is to provide a desirable overall body support firmness and “bounce” when used in conjunction with one or more additional layers of overlying viscoelastic foam and/or non-viscoelastic foam. In other embodiments, base layer 122 may have a hardness of at least about 90 N and no greater than about 190 N. or a hardness of at least about 100 N and no greater than about 180 N. It should be appreciated that unless otherwise specified, the “hardness” of a material referred to herein is measured by exerting pressure from a plate against a sample of the material to a compression of 40% of an original thickness of the material at approximately room temperature (for example, 21 to 23 Degrees Celsius), wherein the 40% compression is held for a set period of time, following the International Organization of Standardization (ISO) 2439 hardness measuring standard.

Base layer 122 may also have a density suitable to provide a reasonable degree of material durability. The density of base layer 122 can impact other characteristics of the foam, such as the manner in which base layer 122 responds to pressure, and the “feel” of the foam layer. Base layer 122 may have a density of no less than about 10 kg/m³ and no greater than about 80 kg/m³. Alternatively, base layer 122 may have a density of at least about 15 kg/m³ and no greater than about 70 kg/m³, or a density of at least about 20 kg/m³ and no greater than about 60 kg/m³.

As shown in FIG. 2, base layer 122 may include an upper or top surface 123 a and a lower or bottom surface 123 b. Top surface 123 a may be provided opposite bottom surface 123 b. Bottom surface 123 b may be substantially: planar, While top surface 123 a may include a plurality of projections or convolutions. The projections or convolutions of top surface 123 a may define a plurality of peaks and valleys. In addition, the projections or convolutions may define one or more passageways between base layer 122 and an associated layer vertically stacked or provided above base layer 122 (for example, intermediate layer 124). The passageways permit movement of air between base layer 122 and an associated layer vertically stacked upon or provided above base layer 122. Such passageways can improve heat transfer within body support 100. For example heat absorbed by one or more layers vertically stacked upon or provided above base layer 122 may be transferred from the layer(s) to the base layer 122. In addition, the passageways can improve heat dissipation from one or more layers vertically stacked upon or provided above base layer 122. The heat dissipation and heat transfer can assist in cooling, or reduce stored heat, of one or more layers vertically stacked upon or provided above base layer 122, including those layers in closest proximity to a user. In sonic alternative embodiments, the top and bottom surfaces may be substantially planar or substantially non-planar. In addition, the top and/or bottom surfaces may include similar or different convolutions or non-planar features, including, but not limited to, ribs, bumps, and other protrusions of any shape or size, and/or surfaces having grooves or other apertures that extend partially or fully through the base layer.

Base layer 122 may include a first thickness T1. First thickness T1 may be provided as the distance between top surface 123 a and bottom surface 123 b. First thickness T1 may be at least about two inches and no greater than about ten inches, and in some embodiments at least about four inches and no greater than about eight inches. In still other embodiments, the first thickness T1 may be about six inches.

In some embodiments, such as the illustrated embodiment of FIGS. 1-4, the base layer 122 is the lowermost layer of the body support 100. However, in other embodiments, the base layer 122 can be supported by one or more underlying layers, such as by another layer of HR foam.

With continued reference to FIG. 2, the intermediate layer 124 may be vertically stacked or provided above base layer 122. Stated otherwise, base layer 122 may be provided below or beneath intermediate layer 124. In addition, intermediate layer 124 may be provided adjacent the base layer 122. Accordingly, base layer 122 may provide support for intermediate layer 174.

Intermediate layer 124 may rest upon base layer 122 without being secured thereto. In the embodiment illustrated in FIG. 2, intermediate layer 124 is secured to base layer 122 by adhesive or cohesive bonding material. In some embodiments, intermediate layer 124 is secured to base layer 122 by a plurality of thin adhesive strips (not shown). The adhesive strips. or the adhesive or cohesive bonding material may be provided between base layer 122 and intermediate layer 124, and may extend across the entire width and/or length of body support 100, or instead may be located in less than all the surface area defining the interface between base and intermediate layers 122, 124. For example, in one embodiment, the adhesive strip material or the adhesive or cohesive bonding material may be located only at edges of the body support 100 to adhere edges of the base and intermediate layers together. Alternatively, the adhesive strip material or the adhesive or cohesive bonding material may be located at discrete, locations across the length and/or width of the body support to spot adhere the base and intermediate layers 122, 124 together. As an additional example, the adhesive strip material or the adhesive or cohesive bonding material may be located in any other manner or location(s) to secure the base and intermediate layers together. Preferably, the adhesive strips or adhesive or cohesive bonding material will have a desired flexibility to form a softer structure than other, more conventional bonding materials. Alternatively, the base and intermediate layers may be bonded together during formation of the layers, or by a coupling assembly, including, but not limited to, tape, hook and loop fastening material, conventional fasteners used in body supports, stitches extending at least partially through the base and intermediate layers 122, 124. or any other suitable fastening material.

Intermediate layer 124 may be formed of a viscoelastic foam. Viscoelastic foam, which is sometimes referred to as “memory foam” or “low resilience foam,” generally partially conforms to the portion of the user supported thereby. in this manner, the force and/or weight applied upon the body support 100 by the Wei is at least partially distributed by the intermediate layer 124. The viscoelastic foam of intermediate layer 124 is a slow recovery foam which slowly returns to its original shape when force and/or weight applied by the user is removed from the foam. Also, the foam of intermediate layer 124 can be a reticulated foam (whether reticulated viscoelastic foam or non reticulated viscoelastic foam).

The intermediate layer 124 of viscoelastic foam may have a hardness of at least about 20 N and no greater than about 80 N for desirable softness and body-conforming qualities. Alternatively, the layer of viscoelastic foam may have a hardness of at least about 30 N and no greater than about 70 N, and in some embodiment a hardness of at least about 40 N and no greater than about 60 N.

The intermediate layer 124 of viscoelastic foam may have a density providing a relatively high degree of material durability. The density of the foam in intermediate layer 124 may also impact other characteristics of the foam, such as the manner in which intermediate layer 124 responds to pressure, and the feel of the foam. The intermediate layer 124 of viscoelastic foam may have a density of no less than about 30 kg/m³ and no greater than about 150 kg/m³. Alternatively, the layer of viscoelastic foam may have a density of at least about 40 kg/m³ and no greater than about 135 kg/m³, and in still other embodiments a density of at least about 50 kg/m³ and no greater than about 120 kg/m³.

The intermediate layer 124 may alternatively be formed of non-viscoelastic foam, and in some embodiments can be made of latex foam. The layer of non viscoelastic foam may have a hardness of at least about 30 N and no greater than about 130 N. This provides a desirable overall body support firmness and “bounce” when used in combination with one or more additional layers of viscoelastic foam (e.g., overlying layers, as described below). Alternatively, the layer of non-viscoelastic foam may have a hardness of at least about 40 N and no greater than about 120 N, and in other embodiments a hardness of at least about 50 N and no greater than about 110 N.

In those embodiments in which the intermediate layer 124 is made of non-viscoelastic foam, the foam of the intermediate layer 124 can have a density of no less than about 40 kg/m³ and no greater than about 100 kg/m³. Alternatively, the layer of non-viscoelastic foam may have a density of at least about 50 kg/m³ and no greater than about 100 kg/m³, and in still other embodiments further a density of at least about 60 kg/m³ and no greater than about 100 kg/m³.

By combining at least one layer of non-viscoelastic foam with at least one layer of viscoelastic-foam, the non-viscoelastic foam layer(s) can increase the “bounce” of body support 100 while retaining benefits of viscoelastic foam, including those described above.

As illustrated in FIG. 2, intermediate layer 124 may include an upper or top surface 125 a and a lower or bottom surface 125 b. Top surface 125 a may be provided opposite bottom surface 125 b. Top and bottom surfaces 125 a, 125 h may be substantially planar. Alternatively, at least one of the top and/or bottom surfaces 125 a, 125 b may be substantially non-planar. In addition, the top and/or bottom surfaces 125 a. 125 b may include similar or different convolutions or non-planar features, including but not limited to, ribs, bumps, and other protrusions of any shape or size, and/or surfaces having grooves or other apertures that extend partially or fully through the intermediate layer.

The intermediate layer 124 may include a second thickness T2. Second thickness T2 may be provided as the distance between top surface 125 a and bottom surface 125 b. Second thickness T2 may be at least about one inch and no greater than about five inches, and in some embodiments at least about one inch and no greater than about four inches. In some embodiments, second thickness T2 may be less than or not greater than first thickness T1.

The uppermost of the foam layers 120 in the illustrated embodiment is a top layer 126 of foam. Top layer 126 may be vertically stacked or provided above intermediate layer 124. Stated otherwise, intermediate layer 124 may be provided below or beneath top layer 126. Accordingly, intermediate layer 124 may provide support for top layer 126. In addition, top layer 126 may be vertically stacked or provided above base layer 122. Stated otherwise, base layer 122 may be provided below or beneath top layer 126. Accordingly, base layer 122 may provide support for top layer 126. In addition, top layer 126 may be provided adjacent to intermediate layer 124.

The top layer 126 may rest upon the intermediate layer 124 without being secured thereto. In the embodiment illustrated in FIG. 2, top layer 126 is secured to intermediate layer 124 by adhesive or cohesive bonding material, or by a plurality of thin adhesive strips (not shown). The top layer 126 can be secured to the intermediate layer 124 in a manner similar to that described above in connection with the base and intermediate layers 122, 124.

In some embodiments, the top layer 126 is formed of viscoelastic foam, including non-reticulated viscoelastic foam or reticulated viscoelastic foam. The viscoelastic foam or non-viscoelastic foam may be substantially as described in association with intermediate layer 124. In other embodiments, including those in which the intermediate layer 124 is made of viscoelastic foam, the top layer 126 is made of non-viscoelastic foam.

As illustrated in FIG. 2, top layer 126 may include an upper or top surface 127 a and a lower or bottom surface 127 b. Top surface 127 a may be provided opposite bottom surface 127 b. In addition, top and bottom surfaces 127 a, 127 b may be substantially planar. Alternatively, at least one of the top and/or bottom surface may be substantially non-planar. In addition, the top and/or bottom surfaces may include similar or different convolutions or non-planar features, including, but not limited to ribs, bumps, and other protrusions of any shape or size, and/or surfaces having grooves or other apertures that extend partially or fully through the intermediate layer.

Top layer 126 may include a third thickness T3. Third thickness T3 may be provided as the distance between top surface 127 a and bottom surface 127 b. Third thickness T3 may be at least about one inch and no greater than about five inches, and in some embodiments may be at least about one inch and no greater than about four inches. In some embodiments, the third thickness T3 is at least about two inches. Generally, third thickness T3 may be greater than, equal to, or less than second thickness T2. In addition. third thickness T3 may be less than or not greater than first thickness T1.

One or more fewer or additional layers of viscoelastic foam and/or high-resilience foam may be included in the foam layers 120. Accordingly, the foam layers 120 may include only two layers of foam, three layers of foam (as illustrated in FIG. 2), or four or more layers of foam.

The foam layers 120 may include a combination of viscoelastic foam and/or high-resilience foam. For example, the foam layers 120 may include a combination of one or more layers of viscoelastic foam vertically stacked on high-resilience foam (e.g., two or more layers of reticulated or non-reticulated viscoelastic foam as described above having different hardnesses and/or densities, atop high-resilience foam). As another example, the foam layers 120 may include a combination of one or more layers of viscoelastic foam vertically stacked on one or more layers of non-viscoelastic foam, with the layers of viscoelastic and non-viscoelastic foam vertically stacked atop high-resilience foam. As yet another example, the foam layers 120 may include alternating layers of one or more layers of viscoelastic foam vertically stacked on one or more layers of non-viscoelastic foam, with the layers of viscoelastic and non-viscoelastic foam being vertically stacked atop high-resilience foam. In addition, it should be appreciated that high-resilience foam may be provided in one or more of the foam lasers 120, and is not limited to or required to be the bottom-most of the foam layers. Accordingly, it should be appreciated that the foam layers 120 may include any number of layers or combination of viscoelastic foam and non-viscoelastic (e.g., high-resilience) foam in accordance with the additional features disclosed herein.

Body support 100 may include phase change material 140, 240 in the foam layers 120. More specifically, phase change material 140, 240 may be provided in each and every layer of the foam layers 120 of body support 100. Phase change material 140, 240 generally provides latent heat storage through a change in phase of the material. For example, and as illustrated in FIGS. 3 and 4, phase change material 140, 240 may be a solid-liquid phase change material. Phase change material 140, 240 may be injected, embedded, or infused throughout each of the foam layers 120. For example, phase change material 140, 240 can be included in the foam material as the foam material is introduced into a mold or upon a substrate for curing or otherwise forming into a foam layer. In addition, phase change material 140, 240 may be introduced into each of the foam layers 120 as a gel, or applied as one or more layers of phase change material.

FIG. 3 illustrates an encapsulated phase change material 140. In the embodiment of FIG. 3, phase change material 142 is contained in a protective capsule 144. Only one protective capsule 144 with phase change material is shown in FIG. 3, it being understood that one more, or all of the foam layers 120 of the body support include a large number of such capsules 144 therethrough. Capsule 144 allows for storage and retention of material 142, especially after material 142 thermally cycles from the solid to liquid phase. Effectively, capsule 144 restricts material 142 from flowing away in an unrestricted manner within the body support when in a liquid phase. A suitable phase change material 142 may be any known or future developed solid-liquid or other phase change material which changes phase between 20 to 35 degrees Celsius. An example of suitable material for protective capsule 144 may be any known or future developed material which conducts heat, restricts leakage, and/or restricts corrosion. A specific example may include, but is not limited to, polypropylene or polyolefin. The encapsulated phase change material 140 may be subject to macro-encapsulation, micro-encapsulation, or molecular-encapsulation. An example of an encapsulated phase change material 140 includes, but is not limited to gel beads.

FIG. 4 illustrates an unencapsulated phase change material 240, or phase change material without encapsulation. Phase change material 240 is substantially the same as phase change material 140, except phase change material 240 does not include protective capsule 144. As such. unencapsulated phase change material 240 generally includes only the phase change material 142. In order to suitably retain unencapsulated phase change material 240 in body support 100. especially when in the liquid phase, the unencapsulated phase change material 240 may be melted and subsequently introduced as a liquid into a mix head prior to the foam formation process. Then, following formation of each foam layer, the unencapsulated phase change material 240 will be retained by the foam which makes up the foam layer.

In those embodiments in which one or more of the foam layers 120 of the body support 100 comprises reticulated foam as described above, encapsulated phase change material may be selected for inclusion in such layers rather than unencapsulated phase change material in order to better retain the phase change material within such layer(s) 120. However, unencapsulated phase change material may still be used in such layer(s) 120 if retained from flowing in other manners. Also, it should be noted that combinations of encapsulated and unencapsulated phase change material can be used in the same body support 100 as desired, such as encapsulated phase change material 142 for one or more layers 120 of the body support 100 (e.g., HR foam layers and/or bottom-most layer(s) 122) and unencapsulated phase change material 142 for the other layers 120 (e.g., intermediate and/or uppermost viscoelastic layers 124, 126).

In operation. solid-liquid phase change material 140, 240 will begin in its solid form. The solid-liquid phase change material 140, 240 will absorb heat, such as heat emitted or generated by a user of body support 100. As the solid-liquid phase change material 140, 240 absorbs heat, the temperature of the phase change material 142 increases. The material. 142 may continue to absorb heat and increase in temperature until the material 142 reaches its melting temperature. Upon achieving its melting temperature, the material 142 changes phase from a solid to a liquid. In some embodiments, during the transition to liquid phase, the phase change material 142 continues to absorb heat at an almost constant temperature. The material 142 continues to absorb heat until all of the material 142 is transformed to its liquid phase. Generally, the material 142 remains in its liquid phase and stores heat until the ambient temperature around the material 142 begins to decrease. For example, the ambient temperature around the material 142 may begin to decrease when a user stops using body support 100. As the ambient temperature decreases or cools, the phase change material 142 solidifies. While solidifying, material 142 releases stored heat to the ambient surroundings of the body support 100.

In some embodiments, one or more of the phase change materials 140, 240 may be provided in each and every layer of the foam layers 120 of body support 100. This includes, but is not limited to, introducing phase change material 140, 240 to viscoelastic foam layers and non-viscoelastic (e.g., HR) foam layers.

By introducing phase change material 140, 240 to each and every of the foam layers 120, body support 100 advantageously improves the relative comfort of a user by absorbing heat generated by the user, while minimizing the temperature increase of the body support 100. This is due to the improved thermal capacity of the body support 100 by incorporating phase change material into each of the foam layers 120 of the body support 100. In addition, when the thermal capacity of the phase change material 140, 240 of the uppermost layer 126 is used (by absorbing all of the user's body heat that can be retained by the phase change material 140, 240 therein), the phase change material 140, 240 within the intermediate layer 124 can begin or continue to absorb heat from the uppermost layer 126. In some embodiments, heat shed from phase change material 140, 240 in the uppermost layer 126 is absorbed by phase change material 140, 240 in the adjacent intermediate layer 124, thereby permitting the phase change material 140, 240 of the uppermost layer 126 to absorb more heat from the user. Similarly, when the thermal capacity of the phase change material 140, 240 of the intermediate layer 124 is used (by absorbing all of the heat that can be retained by the phase change material 140, 240 therein), the phase change material 140, 240 within the base layer 122 can begin or continue to absorb heat from the intermediate layer 124. In some embodiments, heat shed from phase change material 140. 240 in the intermediate layer 124 is absorbed by phase change material 140, 240 in the adjacent base layer 122, thereby permitting the phase change material 140, 240 of the intermediate layer 124 to absorb more heat from the intermediate layer 124. In this manner, rather than block heat from its movement away from the user with a layer of underlying foam having no phase change material properties (and thereby essentially acting as a heat insulator), the phase change material in all layers 120 of the body support 100 acts as a conduit for heat away from the user. In some cases, this resulting heat conduit moves heat to a location where the heat can be shed, such as to or toward a foundation, frame, or other substructure. hi these and other embodiments, the use of a lowermost or base foam layer 122 having phase change material as described above can present significant thermal management advantages for the body support 100 compared to other body supports.

It should also be noted that even in those body supports 100 in which not all foam layers 120 of the body support 100 are provided with phase change material 140, 240 as described above, the use of a lowermost or base foam layer 122 having phase change material 140, 240 can still provide thermal management advantages based upon the principles described above, as can a body support 100 having an HR layer with phase change material 140, 240 in other locations m the body support 100.

By minimizing the temperature increase of the body support 100 during use, the relative comfort of the user is more easily maintained or controlled. Stated otherwise, the body support 100 may more readily control the temperature around the user to a desired relative comfort, as the body support 100 absorbs excess heat generated by the user. In addition, sweating. restlessness, or other symptoms caused by a traditional body support (i.e., without phase change material) that may otherwise adversely affect relative comfort may be reduced by the body support 100. These and other advantages may be realized from one or more embodiments of the body support disclosed herein. 

What is claimed is:
 1. A body support comprising: a plurality of vertically stacked layers; a phase change material provided in each of the layers; and a cover enclosing the vertically stacked layers.
 2. The body support of claim 1, wherein each of the vertically stacked layers is a layer of foam.
 3. The body support of claim 1, wherein the vertically stacked layers include at least one layer of high-resilience foam.
 4. The body support of claim 3, wherein at least one viscoelastic foam layer is provided above the layer of high-resilience foam.
 5. The body support of claim 3, wherein at least one viscoelastic foam layer and at least one non-viscoelastic foam layer is provided above the layer of high-resilience foam.
 6. The body support of claim 5, wherein the at least one viscoelastic foam layer provided above the at least one non-viscoelastic foam layer.
 7. The body support of claim 4, wherein the at least one viscoelastic foam layer is non-reticulated viscoelastic foam.
 8. The body support of claim 3, wherein the vertically stacked layers include at least one layer of non-reticulated viscoelastic foam and at least one layer of a material different than non-reticulated viscoelastic foam.
 9. The body support of claim 8, wherein the at least one layer of non-reticulated viscoelastic foam and at least one layer of a material different than non-reticulated viscoelastic foam are provided above the at least one layer of high-resilience foam.
 10. The body support of claim 9, wherein the at least one layer of a material different than non-reticulated viscoelastic foam is provided beneath the at least one layer of non-reticulated viscoelastic foam.
 11. The body support of claim 1, wherein the phase change material is encapsulated phase change material.
 12. The body support of claim 1, wherein the phase change material is phase change material without encapsulation.
 13. The body support of claim 1, wherein the phase change material is a plurality of gel beads.
 14. The body support of claim 1, wherein encapsulated phase change material is provided in one or more of the vertically stacked layers, wherein phase change material without encapsulation is provided in one or more of the vertically stacked layers, and wherein the encapsulated phase change material and the phase change material without encapsulation are not provided in the same layer.
 15. A body support comprising: a plurality of foam layers, at least one of which is a high-resilience foam; and a phase change material provided within the high-resilience foam layer.
 16. The body support of claim 15, wherein the high-resilience foam layer is the bottom most layer of the plurality of foam layers.
 17. The body support of claim 15, wherein a first of the plurality of foam layers is vertically stacked above the high-resilience foam layer, and wherein the first foam layer includes a phase change material provided within the first foam layer.
 18. The body support of claim 15 wherein the foam layers are provided in a vertically stacked arrangement, and wherein a first of the foam layers is a viscoelastic foam having a phase change material provided within the first foam layer.
 19. The body support of claim 18, wherein the high-resilience foam layer s provided below and supports the first foam layer.
 20. The body support of claim 19, wherein at least one of the plurality of foam layers is a material different than viscoelastic foam and includes a phase change material provided within the layer. 